A machine for converting a substrate is intended for the production of packaging. In this machine, an initial flat substrate, such as a continuous web of cardboard, is unrolled and printed on by a printing station comprising one or more printer units. The flat substrate is then transferred into an introduction unit and then into an embossing unit, possibly followed by a scoring unit. The flat substrate is then cut in a cutting unit. After ejection of the scrap areas, the preforms obtained are sectioned in order to obtain individual boxes.
The rotary conversion, i.e. embossing, scoring, cutting, scrap-ejection, or printer units each comprise a cylindrical upper conversion tool and a cylindrical lower conversion tool, between which the flat substrate passes in order to be converted. In operation, the rotary conversion tools rotate at the same speed but in opposite directions to one another. The flat substrate passes through the gap situated between the rotary tools, which form a relief by embossing, form a relief by scoring, cut the flat substrate into preforms by rotary cutting, eject the scrap, or print a pattern during printing.
The tools can be mounted in a cassette. The cassette allows the operator to adjust the radial gap outside of the machine. On the other hand, this cassette can weigh several hundred kilos and therefore has to be handled with the aid of handling means.
The cylinder changing operations have been found to be time-consuming and tedious. The operator mechanically disconnects the cylinder in order to remove it from its drive mechanism. Then, the operator extracts the cylinder from the conversion machine and fits the new cylinder in the conversion machine by reconnecting it to its drive. The weight of a cylinder is high, around 50 kg to 2000 kg. In order to extract it, the operator lifts it with the aid of handling means.
On account of its fairly high weight, a cylinder cannot be changed very quickly. Moreover, numerous tool changes may be necessary to obtain a very large number of boxes that are different from one another, in order to deal with the increasingly specific requirements made by the customers of printing, embossing, scoring and cutting small runs. These tools have to be ordered a long time in advance, and this is becoming incompatible with the production changes that are currently required. In addition, tools are relatively expensive to produce and they only become cost-effective with an extremely large output.